MORPHOLOGY OF THE STERNAL GLANDS OF 
POLISTES FUSCA TUS AND P. CANADENSIS 
(HYMENOPTERA: VESPIDAE)* 
By David C. Post and Robert L. Jeanne 
Department of Entomology 
University of Wisconsin-Madison 
Madison, Wisconsin 53706 
Although 13 exocrine glands have been located in wasps of the 
genus Polistes, and 12 in Mischocyttarus (Landolt and Akre, 1979), 
their morphology and functions have been little studied. Recently, 
however, the sternal gland on the sixth gastral (terminal) segment of 
females of these wasps has attracted attention because its secretion is 
repugnant to some species of ants. Female wasps rub the secretion 
onto the nest petiole, thus forming a chemical barrier against 
predatory ants (Jeanne, 1970; Hermann and Dirks, 1974; Turillazzi 
and Ugolini, 1978, 1979; Post, 1980). 
Close to the anterior margin of the sternite is a hyaline area covered 
with a tuft of long hairs (‘sternal brush’) (van der Vecht, 1968). In 
Polistes a cluster of gland cells underlies the cuticle on each side of the 
sternal brush (Landolt and Akre, 1979; Turillazzi, 1979). Ducts lead 
from the gland cells to the cuticular surface within the sternal brush. 
A smaller number of gland cells also occurs in a band along the 
anterior margin of the fifth gastral sternite (Hermann and Dirks, 
1974; Turillazzi, 1979). 
We undertook the present study to determine the presence of these 
glands in Polistes fuscatus (F.), a temperate zone species, and in P. 
canadensis (L.), a tropical species, and to compare the size and 
morphology of the glands in these species with those in congeners 
previously investigated by Hermann and Dirks (1974) and Turillazzi 
(1979) 
Materials and Methods 
Adult female foundresses and workers of P. fuscatus (F.) were 
collected in Madison, Wisconsin, on 13 June, 2 and 21 July, and 9 
September, 1978. Adult P. canadensis canadensis (L.) were collected 
*Manuscript received by the editor July 3, 1980. 
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